1. Theory of countercurrent extraction I: equations of optimization and their application;Xu;Acta Sci. Nat. Univ. Pekin. (in Chinese),1978
2. Theory of countercurrent extraction II: purity logarithm diagrammatic method;Xu;Acta Sci. Nat. Univ. Pekin. (in Chinese),1978
3. Theory of countercurrent extraction III: a mathematical model for the dynamic equilibrium of countercurrent extraction;Li;Acta Sci. Nat. Univ. Pekin. (in Chinese),1980
4. Theory of countercurrent extraction IV. Formulas of extreme values of countercurrent extraction parameters and process design;Xu;Rare Metals (in Chinese),1982
5. Theory of countercurrent extraction V. Verification for the formulas for calculation of the numbers of stages of extraction;Li;Rare Metals (in Chinese),1982